Orthopedic anchor assembly

ABSTRACT

An orthopedic assembly is described that comprises an orthopedic device, an anchor, and a locking mechanism. The orthopedic device can be a plate member having an aperture that is configured to receive the anchor. The anchor can include a head, neck and shank portion. The head portion can include a plurality of arms separated by grooves that are capable of splaying. The assembly is configured such that when the locking mechanism is inserted into the head portion, this causes expansion of the arms of the head. This expansion locks and secures the anchor to the orthopedic device. Various instruments are provided that can deliver the locking mechanism to the anchor, and can provide impact to lock functionality.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/148,594, filed May 6, 2016, which is a continuation of U.S. patentapplication Ser. No. 13/273,625, filed Oct. 14, 2011, now U.S. Pat. No.9,358,050, the entire disclosures of which are hereby incorporated byreference in their entireties for all purposes.

FIELD OF THE INVENTION

The present invention is directed to a bone fixation assembly and, inparticular, to an anchor assembly for securing an orthopedic device tobone tissue.

BACKGROUND OF THE INVENTION

In the field of orthopedic surgery, and more specifically spinalsurgery, bone anchors may be used for fixation or for the fastening oforthopedic devices or instruments to bone tissue. An exemplary use ofbone anchors may include using the bone anchors to fasten an orthopedicdevice, such as a bone plate, a spinal rod, or a spinal spacer, to avertebral body for the treatment of a deformity or defect in a patient'sspine. Focusing on the bone plate example, bone anchors can be securedto a number of vertebral bodies and a bone plate can then be connectedto the vertebral bodies via the bone anchors to fuse a segment of thespine. In another example, bone anchors can be used to fix the locationof a spinal spacer once the spacer is implanted between adjacentvertebral bodies. In yet another example, bone anchors can be fastenedto a number of vertebral bodies to anchor a spinal rod in place along aspinal column to treat a spinal deformity.

In each of these exemplary uses, a plurality of bone anchors are neededto fasten the orthopedic device to the area of treatment. In addition,depending on the extent of the disease or size of the defect to betreated, it is possible that several orthopedic devices each requiring aplurality of bone anchors may be required. Accordingly, the fastening ofthe orthopedic implants to the area of treatment can become a timeconsuming and even difficult task.

As such, there exists a need for bone anchors that can quickly andsecurely fasten an orthopedic device to the area of treatment.

SUMMARY OF THE INVENTION

Various embodiments of orthopedic assemblies are provided. In someembodiments, an orthopedic assembly comprises a plate member having anaperture. An anchor is insertable through the aperture of the platemember. The anchor can include a plurality of arms separated by grooves.The assembly further comprises a locking mechanism insertable throughthe anchor. The locking mechanism can include a plurality of fingerscorresponding to each of the arms. Downward insertion of the lockingmechanism through the anchor causes the plurality of arms to splayoutwardly to thereby secure the anchor to the plate member.

In some embodiments, an orthopedic assembly comprises a plate memberhaving an aperture. An anchor is insertable through the aperture of theplate member. The anchor includes a plurality of arms, wherein each ofthe arms includes a slot formed in an inner wall. A locking mechanism isinsertable through the anchor. The locking mechanism includes aplurality of fingers, wherein each finger is insertable into a slot ofthe anchor. Downward insertion of the locking mechanism through theanchor causes the plurality of arms to splay outwardly to thereby securethe anchor to the plate member.

In some embodiments, an orthopedic assembly comprises a plate memberhaving an aperture. An anchor is insertable through the aperture of theplate member. A locking mechanism is insertable through the anchor. Thelocking mechanism is capable of expanding the anchor to secure theanchor to the plate member. An insertion instrument is further providedto deliver the locking mechanism to the anchor via an impaction process.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is an exploded partial perspective view of one embodiment of ananchor assembly;

FIG. 2 is a partial perspective view of the anchor assembly shown inFIG. 1;

FIG. 3 is partial perspective view of the anchor assembly shown in FIG.1;

FIG. 4 is a partial cross-sectional view of the anchor assembly shown inFIG. 1; and

FIG. 5 is a schematic view of another embodiment of an anchor assemblybeing seated and locked in an orthopedic device.

FIG. 6A is a side view of an alternative anchor according to someembodiments.

FIG. 6B s a cross-sectional view of the anchor in FIG. 6A with analternative locking mechanism according to some embodiments.

FIG. 6C is a top view of the anchor and locking mechanism in FIG. 6B.

FIG. 7A is a side view of an alternative locking mechanism according tosome embodiments.

FIG. 7B is cross-sectional view of the locking mechanism in FIG. 7A.

FIG. 7C is a top view of the locking mechanism in FIG. 7A.

FIG. 8A is a cross-sectional view of a first position of a lockingmechanism in an anchor according to some embodiments.

FIG. 8B is a cross-sectional view of a second position of a lockingmechanism in an anchor according to some embodiments.

FIG. 9A is a side view of an orthopedic device assembly according tosome embodiments.

FIG. 9B is a cross-sectional view of the orthopedic device assembly inFIG. 9A.

FIGS. 10A-10I illustrate different views of a multi-functional insertioninstrument according to some embodiments.

FIGS. 11A and 11B illustrate different views of an alternativemulti-functional insertion instrument according to some embodiments.

FIGS. 12A-12D illustrate different views of an alternativemulti-functional insertion instrument according to some embodiments.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

The following description of the preferred embodiments is merelyexemplary in nature and is in no way intended to limit the invention,its application, or uses.

With reference to FIGS. 1-4, a preferred embodiment of an anchorassembly 10 is illustrated. The anchor assembly 10 preferably includesan anchor 11 and a locking mechanism 30. Although the anchor 11 will bediscussed in the context of an orthopedic screw, it is contemplated thatthe anchor 11 can be any type of anchoring element including, but notlimited to, a hook, a pin, or a nail. In a preferred embodiment, theanchor 11 includes, concentric to a longitudinal axis 12, a head portion14, a neck portion 18 and a shank portion 16. The head portion 14connects to the shank portion 16 through the neck portion 18. The anchorassembly 10 is preferably constructed from any biocompatible materialincluding, but not limited to, stainless steel alloys, titanium,titanium based alloys, or polymeric materials.

In a preferred embodiment, the head portion 14 of the anchor 11 has agenerally spherical shape and includes at least one resilient fingerelement 20. In another preferred embodiment, the head portion 14includes four resilient finger elements 20. Preferably, located oneither side of the resilient finger element 20 is an elongated groove22. The grooves 22 may be configured and dimensioned to correspond withthe end of a driving instrument (not shown) designed to engage theanchor 11, and consequently the anchor assembly 10.

As best shown in FIG. 4, the generally spherical shape of the headportion 14 is configured and dimensioned to be received within acorrespondingly shaped cavity 52 in an orthopedic device 50 which may bepart of a spinal fixation system. In an exemplary embodiment, theorthopedic device 50 is a bone plate, but the orthopedic device can beany device, such as a spinal rod “tulip” style holder or a spinalspacer. The shape of the head portion 14 and the correspondingly shapedcavity 52 allows the anchor assembly 10 to pivot, rotate and/or movewith respect to the orthopedic device 50. In another embodiment, insteadof allowing the anchor assembly 10 to pivot, rotate and/or move withrespect to the orthopedic device 50, the head portion 14 and thecorrespondingly shaped cavity 52 may be configured and dimensioned tokeep the anchor assembly 10 in a fixed position. In an exemplary use,the head portion 14 of the anchor 11 is received in the cavity 52 of theorthopedic device 50 and the anchor assembly 10 is pivoted, rotated ormoved until the desired orientation with respect to the orthopedicdevice 50 is met. The anchor assembly 10 is then locked in place, whichis discussed in detail below, in the cavity 52 of the orthopedic device50. In a preferred embodiment, the head portion 14 also includestexturing 24 that extends along at least a portion of the head portion14. The texturing 24 on the head portion 14 provides additionalfrictional surfaces which aid in locking the anchor assembly 10 in placewith respect to the orthopedic device 50.

Turning back to FIGS. 1-3, in a preferred embodiment, the neck portion18 of the anchor 11 integrally connects the head portion 14 with theshank portion 16. The diameter of the neck portion 18 is preferablydimensioned to match the minor diameter of the anchor 11. By having thediameter of the neck portion 18 dimensioned at least as large as theminor diameter of the anchor 11, the overall rigidity and strength ofthe anchor 11 is increased.

In a preferred embodiment, the shank portion 16 of the anchor 11includes a shaft 26 surrounded at least in part by a thread portion 28.The diameter of the shaft 26 is the minor diameter of the anchorassembly 10. In a preferred embodiment, the diameter of the shaft 26remains generally constant from a proximal end of the shaft 26 toward adistal end of the shaft 26. The constant diameter of a majority portionof the shaft 26 allows for optimal anchor positioning when the anchorassembly 10 is inserted into a predetermined area in the bone tissue.The constant diameter also allows for varying the depth positioning ofthe anchor assembly 10 in the bone. For example, if a surgeon places theanchor assembly 10 into bone tissue at a first depth and decides theplacement is more optimal at a second, shallower depth, the anchorassembly 10 can be backed out to the second depth and still remain fixedin the bone. In another embodiment, the diameter of the shaft 26 mayvary along its length, including increasing in diameter from theproximal end to the distal end or decreasing in diameter from theproximal end to the distal end.

With continued reference to FIGS. 1-3, the thread portion 28 surroundingthe shaft 26 extends, in a preferred embodiment, from the distal end ofthe shaft 26 to the neck portion 18. In another preferred embodiment,the thread portion 28 may extend along only a portion of shaft 26. Thethread portion 28 is preferably a Modified Buttress thread but thethread can be any other type of threading that is anatomicallyconforming, including, but not limited to Buttress, Acme, Unified,Whitworth and B&S Worm threads.

In a preferred embodiment, the diameter of the thread portion 28decreases towards the distal end of the anchor 11. By having a decreaseddiameter thread portion 28 near the distal end of the anchor 11, theanchor 11 can be self-starting. In another preferred embodiment, anchor11 may also include at least one flute to clear any chips, dust, ordebris generated when the anchor assembly 10 is implanted into bonetissue.

Looking again at FIGS. 1-4, the anchor assembly 10 preferably includesthe locking mechanism 30. In a preferred embodiment, the lockingmechanism 30 will lock the anchor assembly 10 with respect to theorthopedic device 50 thereby preventing the anchor assembly 10 fromdisengaging from the orthopedic device 50. The locking mechanism 30preferably includes a locking member 32 which is configured anddimensioned to be received in an opening 34 in the anchor 11.

In a preferred embodiment, the locking member 32 has a head member 36and a shaft member 38. The head member 36 preferably includes an opening40 for receiving a driving instrument (not shown). The opening 40 mayalso include threading 42 that is capable of threadingly engaging adriving instrument for reasons explained below. In a preferredembodiment, the shaft member 38 includes at least one protrusion 44extending along at least a portion of the circumference of the shaftmember 38. Focusing on FIG. 4, at least a portion of the shaft member38, in a preferred embodiment, also includes a hollow portion 46 whichallows at least a portion of the shaft member 38 surrounding the hollowportion 46 to flex inwardly.

Turning back to FIGS. 1 and 4, the opening 34, preferably, is generallyannular and extends coaxially with the longitudinal axis 12 from thehead portion 14 through the neck portion 18 into the shank portion 16.The opening 34 preferably also includes at least two recesses 47, 48,each recess 47, 48 extending along at least a portion of thecircumference of the opening 34. Each recess 47, 48 is configured anddimensioned to accommodate the protrusion 44.

In an exemplary use of the anchor assembly 10 with the orthopedic device50, the orthopedic device 50 is first oriented and placed in the area oftreatment. The orthopedic device 50 is then fastened to the bone tissuevia at least one anchor assembly 10 which is received in at least onecavity 52 of the orthopedic device 50. Looking at FIG. 4, in a preferredembodiment, the cavity 52 has a generally spherical shape with a firstdiameter y at an upper portion 54. When viewed from the upper portion 54to a lower portion 56, the diameter of the cavity 52 generally increasesuntil approximately the middle portion of the cavity 52. The diameter ofthe approximately middle portion of the cavity 52 is a second diameterx. The diameter of the cavity 52 then decreases from the approximatelymiddle portion of the cavity 52 to the lower portion 56, where thediameter of the cavity near the lower portion 56 is the same as orsmaller than the first diameter y.

In a preferred embodiment, the anchor assembly 10 passes through thecavity 52 until the head portion 14 of the anchor 11 abuts the topportion 54 of the cavity 52. As can be seen in FIG. 4, in a preferredembodiment, the diameter of the head portion 14 of the anchor 11 isgenerally the same width as diameter x. Since the top portion 54 of thecavity 52 has a diameter y, which is smaller than the diameter x, as thehead portion 14 is brought into the cavity 52, the finger elements 20 ofthe head portion 14 resiliently bias inwardly reducing the diameter ofthe head portion 14 until the head portion 14 fits through top portion54 of the cavity 52. Once the head portion 14 passes through the topportion 54, the resilient finger elements 20 return back to theiroriginal position as the head portion 14 is seated in the cavity 52.

As best seen in FIGS. 3 and 4, in a preferred embodiment, once theanchor assembly 10 is seated in the cavity 52, the anchor assembly 10can be locked in the cavity 52 by actuating the locking mechanism 30. Ina preferred embodiment, a user actuates locking mechanism 30 by pushingon the head member 36 of the locking member 32. The downward force movesthe locking member 32 further into the opening 34. As the locking member32 moves into the opening 34, the protrusion 44 will disengage from therecess 47. Since, in a preferred embodiment, the diameter of the shaftmember 38 of the locking member 32 is generally equivalent to thediameter of the opening 34 near the neck portion 18 and the shaftportion 16, the shaft member 38 will flex inwardly, aided by the hollowportion 46, to accommodate the protrusion 44 once it disengages from therecess 47. The locking member 32 will continue to move further intoopening 34 until the protrusion 44 engages the recess 48 at which pointthe head member 36 will be seated between the resilient finger elements20 of the head portion 14. The anchor assembly 10 is now locked in thecavity 52 since the head member 36, once seated between the resilientfinger elements 20, prevents the resilient finger elements 20 fromflexing inwardly. It is important to note that the disengagement ofprotrusion 44 from recess 47 and the engagement of the protrusion 44with the recess 48 (and vice versa) provides the user with audibleand/or tactile feedback allowing the user to quickly and easily confirmthe locked or unlocked status of the anchor assembly 10.

As mentioned earlier, the head portion 36 includes the opening 40 whichmay include threading 42. The threading 42 in opening 40 engages adriving instrument (not shown) allowing a user to pull on the lockingmechanism 30 thereby unlocking the anchor assembly 10 in the event auser wants to disengage the anchor assembly 10 from the orthopedicdevice 50.

In another exemplary use of the anchor assembly 10 with the orthopedicdevice 50, the orthopedic device 50 is first oriented and placed in thearea of treatment. The orthopedic device 50 is then fastened to the bonetissue via at least one anchor assembly 10 which is received in at leastone cavity 52 of the orthopedic device 50. In this exemplary use, afterthe anchor assembly 10 is seated in the cavity 52, but before the anchorassembly 10 is locked in the cavity 52, the anchor assembly 10 ispivoted, rotated or otherwise moved until the desired orientation withrespect to the orthopedic device 50 is met. The anchor assembly 10 isthen locked in place at that desired orientation by actuating thelocking mechanism 30 as discussed above.

In this exemplary use, to lock the anchor assembly 10 at the desiredorientation another preferred embodiment of the anchor assembly 10, andmore specifically, another preferred embodiment of the locking mechanism30 is necessary. In this preferred embodiment, the locking mechanism 30is configured and dimensioned to resiliently bias the resilient fingerelements 20 of head portion 14 outwardly when the locking mechanism 30is pushed from the first, unlocked position, to the second, lockedposition. By resiliently biasing the finger elements 20 outwardly, thefinger elements 20 will push against the walls of the cavity 52 therebylocking the anchor assembly 10 in place in the desired orientation. Toresiliently bias the finger elements 20 outwardly, the head member 36 ofthe locking mechanism 30, preferably, is configured and dimensioned toinclude tapering surfaces and a diameter larger than the diameter of theopening 34 near the head portion 14.

Turning to FIG. 5, a preferred embodiment of the anchor assembly 100 isshown. The anchor assembly 100 is similar to anchor assembly 10, assuch, only the differences between the two embodiments are addressedherein. The anchor assembly 100 preferably includes an anchor 110 and alocking mechanism 130. In a preferred embodiment, the anchor 110includes, concentric to a longitudinal axis 112, a head portion 114, aneck portion 118 and a shank portion 116. The head portion 114 connectsto the shank portion 116 through the neck portion 118. In a preferredembodiment, the head portion 114 of the anchor 110 has a generallyspherical shape and includes a resilient ring element 120 capturedbetween an upper and lower end of the head portion 114.

With continued reference to FIG. 5, in a preferred embodiment, thelocking mechanism 130 will lock the anchor assembly 100 with respect tothe orthopedic device 150 thereby preventing the anchor assembly 100from disengaging from the orthopedic device 150. The locking mechanism130 preferably includes a locking member 132 which is configured anddimensioned to be received in an opening 134 in the anchor 110.

In an exemplary use of the anchor assembly 100 with the orthopedicdevice 150, the orthopedic device 150 is first oriented and placed inthe area of treatment. The orthopedic device 150 is then fastened to thebone tissue via at least one anchor assembly 100 which is received in atleast one cavity 152 of the orthopedic device 150. In a preferredembodiment, the anchor assembly 100 passes through the cavity 152 untilthe head portion 114 of the anchor 110 abuts a top portion of the cavity152. Since the top portion of the cavity 152 has a diameter that issmaller than the diameter of the head portion 114, to fit the headportion 114 into the cavity 152, the resilient ring 120 is resilientlybias inwardly, reducing the diameter of the head portion 114, until thehead portion 14 fits through top portion of the cavity 152. Once thehead portion 114 passes through the top portion of the cavity 152, thering 120 returns back to its original position as the head portion 114is seated in the cavity 152.

With continued reference to FIG. 5, in a preferred embodiment, once theanchor assembly 100 is seated in the cavity 152, the anchor assembly 100can be locked in the cavity 152 by actuating the locking mechanism 130.In a preferred embodiment, a user actuates locking mechanism 130 bypushing on the locking member 132. The downward force moves at least aportion of the locking member 132 into opening 134. The anchor assembly100 is now locked in the cavity 152 since the locking member 132, onceseated in the opening 134, prevents the ring 120 from flexing inwardly.

Additional Embodiments of Locking Bone Screw Assemblies

Additional embodiments of an alternative locking bone screw assemblyincluding an anchor and locking mechanism are described. The assemblyallows the anchor to be secured to an orthopedic device, such as a boneplate. The alternative locking bone screw assembly comprises an anchorwith splaying arms and an insertable locking mechanism that forces thearms to splay, thereby expanding the arms of the anchor. When the armsof the anchor are expanded, the arms press against the surface of theorthopedic device, thereby causing fixation between the anchor theorthopedic device. For example, the anchor can be positioned in anaperture of an orthopedic plate member. Before expansion of the anchor,the anchor is free to move about in multiple orientations and directionsrelative to the orthopedic plate. Following expansion, the walls of theanchor are pressed firmly against the walls of the orthopedic platemember, thereby helping to retain the anchor within the plate member andform an assembly. In other words, in some embodiments, there is nolocking interference between the anchor and the orthopedic plate memberprior to expansion and splaying of the anchor. After the walls of theanchor have been splayed into a different locking diameter, the anchoris securely fixed to the plate member. The advantage of this assembly isthat it includes a locking mechanism that does not require an axialforce to overcome a locking element or a certain amount of threadpurchase to operate the locking feature. In addition, the position ofthe locking mechanism provides a clear visual indication of whether theanchor is locked or unlocked. Moreover, the anchor can be easily removedfrom the orthopedic device without ruining the orthopedic device usingthe locking mechanism described herein.

FIG. 6A is a side view of an alternative anchor according to someembodiments. The anchor 211 includes a head portion 214, a neck portion218 and a shank portion 216. The anchor 211 is designed to fit throughan aperture of an orthopedic device (e.g., a plate member) to secure thedevice to a treatment site.

The anchor head portion 214 comprises an upper opening for receiving alocking mechanism 230, as shown in FIG. 6C. The head portion 214comprises two or more resilient members in the form of fingers or arms220 that are separated by grooves 222. In the illustrated embodiment,the head portion 214 comprises four arms 220, each of which is separatedby a single groove. The arms 220 are advantageously capable of splayingoutwardly from a central axis of the anchor 211 when a force is applied.In some embodiments, the splaying force can be applied by inserting alocking mechanism 230 having splay fingers 232 (shown in FIGS. 7A-7C)into the head portion 214. The locking mechanism 230 forces the outwardexpansion of the arms 220 of the head portion 214.

While in the illustrated embodiment, the head portion 214 comprises fourarms 220 separated each by a groove 222, such that each adjacent groove222 is at approximately a 90 degree angle from one another, the headportion 214 can also include other configurations. For example, the headportion 214 can include three arms, each of which is separated bygrooves. In this situation, adjacent grooves can be approximately 120degrees away from another. In some embodiments, more than four arms 220are formed in the head portion, such as five, six, seven, eight or more.In addition, the adjacent grooves 222 can also be separated by greaterthan or less than 90 degree angles. Moreover, while the grooves 222 areillustrated as symmetrical, in other embodiments, the grooves 222 areasymmetrical.

The anchor head portion 214 transitions into the shank portion 216 viathe neck portion 218. In some embodiments, the neck portion 218 includesone or more relief cuts 219 that are machined along at least a portionof the neck. The relief cuts 219 advantageously accommodate andfacilitate the splaying of the arms 220 of the head portion. Theorientation of the relief cuts 219 allows the arms to splay easier intheir outward directions. In some embodiments, the relief cuts 219 arepositioned at a bottom end of a pocket of the anchor head to enhance theability of arms to flex outwardly away from the central axis of theanchor.

The shank portion 216 comprises an extended shaft that can be insertedinto a bone member. While the shank portion 216 is illustrated as havingno threads, in other embodiments, the shank portion 216 comprises aplurality of threads that extend along at least a portion of its length.The threads can be single diameter threads or dual diameter threads.

FIG. 6B s a cross-sectional view of the anchor 211 in FIG. 6A with alocking mechanism 230 inserted therein according to some embodiments.The locking mechanism 230 includes a plurality of splay fingers 232,each of which engages an inner wall 227 of at least one arm 220 of thehead portion 214. In some embodiments, one or more of the inner walls227 of the head portion arms 220 include a groove or slot 234 forreceiving a splay finger of the locking mechanism 230, as shown in FIG.6C. As the locking mechanism 230 is inserted downwardly into the headportion 214, the splay fingers 232 of the locking mechanism slide downthe slots 234 in the head portion and force the head portion to splayand expand outwardly. In some embodiments, the splay fingers 232 of thelocking mechanism are tapered. The slots 234 for receiving the splayfingers 232 in the anchor can also be tapered. Advantageously, inaddition to facilitating the splaying of the anchor arms, the slots 234in the anchor 211 also assist in guiding the locking mechanism 230 intothe proper orientation within the anchor 211.

FIG. 6C is a top view of the anchor and locking mechanism in FIG. 6B. Asshown from this viewpoint, the splay fingers 232 of the lockingmechanism 230 are slidably inserted into the slots 234 along the innerwall of the anchor arms 220, thereby forcing outward expansion of thehead of the anchor.

The top of the locking mechanism 230 is visible in FIG. 6C. As shown inthe figure, the top of the locking mechanism 230 can include a centralcircular portion 233 that is suitable for instrument engagement. Inaddition, the central circular portion 233 of the locking mechanism 230advantageously maintains a centralized locking force between the lockingmechanism 230 and the anchor 211, thereby allowing for an equal forcedistribution amongst the splay fingers 232.

FIG. 7A is a side view of an alternative locking mechanism according tosome embodiments. The locking mechanism 230 includes an upper headportion 236 comprising one or more splay fingers 232 and a lower shaftportion 238. In the illustrated embodiment, the locking mechanism 230includes four splay fingers 232 a, 232 b, 232 c and 232 d. The splayfingers 232 engage the inner walls of the arms of the anchor head,thereby promoting splaying of the anchor head.

As shown in FIG. 7A, the lower shaft portion 238 of the lockingmechanism can include one or more compression slots 241. In theillustrated embodiment, the compression slot 241 extends from a pointwithin the shaft portion 238 to a distal end of the shaft portion 238.When the locking mechanism 230 is inserted into the anchor 211, thelower shaft portion 238 can compress against inner walls of the anchor(as shown in FIG. 6B), thereby advantageously facilitating insertion ofthe locking mechanism 230 within the anchor 211.

FIG. 7C is a top view of the locking mechanism in FIG. 7A. The splayfingers 232 a, 232 b, 232 c and 232 d are illustrated as symmetricalabout the central circular portion 233. This symmetry advantageouslyallows forces to be evenly distributed around the locking mechanism. Inother embodiments, the splay fingers 232 need not be symmetrical aboutthe central circular portion.

FIG. 8A is a cross-sectional view of a first position of a lockingmechanism 230 in an anchor 211 according to some embodiments. As shownin the figure, portions of the outer arms 220 of the anchor 211 contactthe inner walls of an orthopedic device in the form of a plate 250;however, as the locking mechanism 230 is not fully inserted down throughthe anchor 211, the arms 220 of the anchor are not splayed outwardly andthus, the anchor 211 is free to move about relative to the plate 250. Inthis first position, the locking mechanism 230 is in the process ofbeing inserted into the head portion of the anchor 211. As shown in thefigure, the top of the locking mechanism 230 is proud above a topsurface of the anchor 211. In this first position, the arms 220 of theanchor 211 are not yet fully splayed and pressed firmly against theinner wall, such that the orientation and position of the anchor 211 canstill be adjusted relative to the plate 250.

FIG. 8B is a cross-sectional view of a second position of a lockingmechanism 230 in an anchor 211 according to some embodiments. In thisfigure, the locking mechanism 230 has been inserted further down theanchor 211, thereby forcing the arms 220 of the anchor to splayoutwardly. When the anchor arms 220 are splayed outwardly, they pressagainst the inner walls of the plate 250, thereby forming a secure fit.The position and angle of the anchor 211 is thus fixed relative to theplate 250, thereby forming a secure assembly.

FIG. 9A is a side view of an orthopedic device assembly 300 according tosome embodiments. The assembly 300 comprises a plate member 250 securedto an anchor 211. By inserting a locking mechanism 230 into an upperopening of the anchor 211, arms of the anchor can splay outwardly,thereby securing the anchor 211 to the plate member 250.

FIG. 9B is a cross-sectional view of the orthopedic device assembly inFIG. 9A. From this viewpoint, one skilled in the art can appreciate thatthe locking mechanism 230 is in the process of being fully inserted intoanchor 220 to thereby secure the anchor 220 to the plate member 250.

Methods of using the locking assembly are now provided. In someembodiments, an orthopedic device, such as a plate member, can beoriented and placed in an area of treatment. The orthopedic deviceincludes one or more apertures for receiving anchor members to securethe orthopedic device to the treatment area. An anchor member can beinserted through an aperture of the orthopedic device. The anchor memberis free to move in different positions and/or orientations relative tothe orthopedic device until a locking mechanism is inserted therein. Thelocking mechanism can comprise one or more splaying arms that engage theinner walls of the anchor member, thereby causing expansion of theanchor member within the orthopedic device. Once the anchor member isexpanded, the anchor member is secured to the orthopedic device, therebyforming a secure assembly.

Multi-Functional Instruments

Novel instruments are now described that cooperate with the locking bonescrew assemblies described above, and in particular, those in FIGS.6A-9B. The instruments are advantageously multi-functional and can helpto both drive an anchor into a bone member and provide the lockingmechanism to secure the anchor to an orthopedic device such as a platemember. The multi-functional instruments can advantageously provide anovel “impact to lock” feature that secures the anchor to orthopedicdevice.

FIGS. 10A-10I illustrate different views of a multi-functional insertioninstrument according to some embodiments. The insertion instrument 400comprises a proximal portion 402 comprising a handle 410 and a distalportion 405. The distal portion 405 can hold a locking mechanism, suchas those shown in FIGS. 7A-7C.

The multi-functional insertion instrument 400 is configured toadvantageously accommodate three different features: a drive feature, acocking/setting feature and a catch and release feature. The drivefeature allows an anchor, such as that shown in FIGS. 6A-6C, to bedriven into a bone member. The cocking feature prepares a lockingmechanism, such as that shown in FIGS. 7A-7C, for impaction into theanchor so as to secure the anchor to an orthopedic device. The catch andrelease feature operates with the cocking feature, and serves toforcefully release the locking mechanism into the anchor. The catch andrelease feature uses an impaction force to drive the locking mechanisminto the anchor, thereby causing expansion of the anchor to secure theanchor to an orthopedic device. The instrument thus relies on a novel“impact to lock” concept that is not found in other instruments. Thefeatures of the instrument 400 that support these multiple features arenow discussed in detail.

FIG. 10A illustrates a side cross-sectional view of the multi-functionalinsertion instrument 400. As shown in the figure, a number of featuresare enclosed within a housing 411 of the handle 410 in a proximalportion 402 of the instrument. A drive shaft 419, which relates to thedrive feature, extends from within the handle 410 to a distal portion405 (shown in FIG. 10B) of the instrument. A cocking sleeve 422 alsoextends from within the handle 410 to a more distal portion outside ofthe handle of the instrument. The cocking sleeve 422 moves in contactwith one or more cocking pins 426 to move a hammer shaft 431 axiallyalong the instrument. The cocking pins 426 and hammer shaft 431 arefully contained within the handle 410. The cocking sleeve 422, cockingpins 426, and hammer shaft 431 relate to the cocking feature thatprepares a locking mechanism for impact to lock. The hammer shaft 431interacts with catch pins 442 which capture the hammer shaft prior toimpact to lock. A button 452 is provided to release the hammer shaft 431from the catch pins 442, thereby forcing a locking mechanism on a distalend of the instrument 400 into an anchor. The catch pins 442 and button452 thus relate to the release feature of the instrument.

Instrument components related to the drive feature are shown in FIG.10C. FIG. 10C illustrates a perspective view of an interior section ofthe handle 410, as well as a drive shaft 419 that extends through theinterior section. The drive shaft 419, which can be used to drive ananchor into bone, includes a keyed pattern portion 463 that mates with acomplementary keyed pocket 461 formed on a flat surface 421 within thehandle 410. While in the illustrated embodiment, the keyed patternportion 463 of the drive comprises a plurality of extending protrusions,other designs are also possible so long as it mates and aligns with thekeyed pocket 461. For example, in some embodiments, the pattern portioncan comprise a parallelogram with a plurality of edges that rests in acomplementary pocket within the handle. The alignment between the keyedpattern portion 463 of the drive and the keyed pocket 461 within thehandle advantageously provides an anti-torsion feature that allows thehandle 410 to rotate and drive an anchor into bone, while stillmaintaining the ability to perform the cocking feature and catch andrelease feature discussed above.

Instrument components related to the cocking feature are shown in FIGS.10D and 10E. FIG. 10D illustrates a perspective cross-sectional view ofan interior section of the handle 410, including a cocking sleeve 422and cocking pins 426. FIG. 10E also illustrates a perspectivecross-sectional view of an interior section of the handle 410 andfurther includes the shaft hammer 431.

As shown in FIG. 10D, the instrument 400 includes a cocking shaft 422that extends beyond a distal portion of the handle. The cocking shaft422 is configured to move up and down axially along a length of thehandle. In some embodiments, the cocking shaft 422 is operated manually,such as by fingers of a user.

The cocking shaft 422 is operably connected to a plurality of cockingpins 426. The cocking pins 426 extend through machined holes 416 formedin the flat surface 421 within the handle. Axial movement of the cockingshaft 422 simultaneously moves the cocking pins 426 along a length ofthe handle. While the illustrated embodiments illustrates three cockingpins 426, more or less than three pins can be provided to assist insetting the instrument.

As shown in FIG. 10E, the top portion of the cocking pins 426 cancontact the hammer shaft 431. The hammer shaft 431 comprises a discportion 433 with an extended shaft 432 therein. The upper portion 434 ofthe hammer shaft 431 is chamfered to aid in the splaying of the catchpins, as shown in FIG. 10G. The distal portion of the hammer shaft 431(not shown) is attached to a locking mechanism, such as that shown inFIG. 7A. When the cocking pins 426 move axially upward along the handle,the cocking pins 426 can push up against the bottom of the disc portion433 of the hammer shaft 431, thereby causing the hammer shaft 431 tomove upwards. As the hammer shaft 431 moves upwards, it is placed into a“firing position,” whereby it is captured and then released to performan impact to lock feature, as discussed below.

Instrument components related to the catch and release feature are shownin FIGS. 10F-10I. FIG. 10F illustrates a perspective cross-sectionalview of the hammer shaft 431 prior to setting the hammer shaft into afiring position. FIG. 10G illustrates a front schematic view of thehammer shaft 431 in the process of being loaded into a firing positionwith the assistance of catch pins 482. FIG. 10H illustrates aperspective cross-sectional view of the hammer shaft 431 in the processof being loaded into a firing position. FIG. 10I illustrates a frontschematic view of the hammer shaft 431 in the process of being releasedor fired.

The catch and release feature of the instrument 400 relies on one ormore catch pins 482 which travel in a set of grooves, one of which ispositioned in the housing perpendicular to a central longitudinal axisand another which is positioned proximate a release button. The catchpins 482 are designed to capture the upper portion 434 of the hammershaft 431 to retain the hammer shaft 431 prior to release and impaction.As shown in FIG. 10G, as the hammer shaft 431 moves upwardly, the upperportion 434 of the hammer shaft 431 pushes and contacts the catch pins482. The chamfered surfaces of the upper portion 434 advantageously aidin the perpendicular splaying of the catch pins 482, as shown in FIG.10G. After splaying outwardly, the catch pins 482 return to capture abottom section of the upper portion 434 of the hammer shaft 434, therebycapturing and retaining the hammer shaft 431 in a position prior tofiring and release. When the hammer shaft 431 is ready for release, therelease button 452 can be pushed. Pushing the release button 452 causesthe pins to 482 to splay outwardly at an angle away from a centrallongitudinal axis of the instrument 400, as shown in FIG. 10, therebycausing the hammer shaft 431 to be released from capture. The releasedhammer shaft 431 drops downwardly to impact and lock the lockingmechanism into the anchor, thereby securing the anchor to the orthopedicdevice.

As shown in FIGS. 10F-10I, the hammer shaft 431 can comprise a springmember 479 positioned between the lower flat surface 421 and the upperchamfered portion 434 of the hammer shaft 431. Accordingly, the hammershaft 431 can comprise a spring-loaded device that is capable of captureand release to force impact of the locking mechanism into the anchor.

Advantageously, the instrument 400 can thus serve to both insert ananchor into a bone member and to secure the anchor to an orthopedicdevice. Both of these functions can be performed simultaneously oralternatingly.

FIGS. 11A and 11B illustrate different views of an alternativemulti-functional insertion instrument according to some embodiments.Like the previously described insertion instrument, the insertioninstrument 500 is configured to both drive an anchor into a bone memberand to impact a locking mechanism into the anchor to secure the anchorto an orthopedic device. However, unlike the previously describedinsertion instrument, instrument 500 includes a catch and releasefeature that is positioned outside of the handle body. FIG. 11Aillustrates a perspective view of the insertion instrument 500, whileFIG. 11B illustrates a close-up of the external catch and releasefeature of the instrument 500.

As shown in FIG. 11A, the insertion instrument 500 includes a proximalportion 502 comprising a handle and a distal portion 505. The distalportion 505 can grasp a locking mechanism to impact into an anchor (notshown). Within the proximal portion, a hammer shaft 531 can moveupwardly. The hammer shaft 531 can operate with a spring or coil member579 to generate spring-loaded forces to impact a locking mechanism intoan anchor.

The catch and release feature of the insertion instrument is shown upclose in FIG. 11B. The catch and release feature comprises a catchmember 526 and a release member 522 that are operably connected and movetogether as a unit. The catch member 526 includes a catching location538 for catching a pin member 535 on the hammer shaft 531. The releasemember 526 includes a release spring 523 that cooperates with the catchmember 526. As the hammer shaft 531 is moved upwardly, the pin member535 can be received in the catching location 538 of the catch member 526in preparation for release and impaction.

As shown in FIG. 11B, the catch member 526 includes a flange that actsas a stop for release member 522. The assembly includes a counterbore537 in the handle 510 that accepts the flange and acts as a stop withthe flange. To cock and set the instrument, the hammer shaft 531 ispushed axially upwards towards the handle 510. During this movement, therelease spring 523 is compressed, thereby moving the catch member 526off the main axis. This movement allows the pin member 535 of the catchmember to gain access to the groove formed in the catching location 538.At this point, the hammer shaft 531 is prepared for release andimpaction. To release the hammer shaft 531, the release member 526 canbe pushed, thereby moving the catch member until the pin finds thegroove in the catching location 538. Upon release of the hammer shaft531, this causes impaction of a locking mechanism into an anchor,thereby securing the anchor to an orthopedic device.

FIGS. 12A-12D illustrate different views of an alternativemulti-functional insertion instrument according to some embodiments. Theinstrument 600 comprises a proximal portion 602 comprising a handle 610,a mid-sleeve 612 and a distal portion 605 that can be secured in series.These three components form a housing that encloses a firing spring 618and firing cylinder 622 near the proximal portion 602 of the instrument,and a release spring 628 and swivel release 633 near the distal portion605 of the instrument. The distal portion 605 of the instrument 600 alsoencloses a grasping element 661 having a distal tip 663 (as shown inFIG. 12D) for grasping the head of a locking mechanism.

The interaction of the swivel release 633 with the firing cylinder 622helps form an impaction mechanism on the grasping element 661 that canforce a locking mechanism into the head of an anchor. Unlike thepreviously described instruments, instrument 600 does not include acatch and release function. Rather, the instrument 600 relies on thealignment of the swivel release 633 to trigger an impaction mechanism toimpact the locking mechanism into the head of the anchor, as discussedin more detail below.

The swivel release 633 comprises a body portion 634 that transitionsinto an extended narrower tip portion 635 via tapered sidewalls 637. Thenarrower tip portion 635 extends in the direction of the handle 610.During use, the swivel release 633 is retained at least in part within arelease spring 635. In its natural state, the swivel release 633 is notaligned with a central longitudinal axis of the instrument 600. In thisstate, the narrower tip portion 635 of the swivel release will becrooked and oriented at an angle (e.g., misaligned) from the centrallongitudinal axis. This misalignment creates an interference thatcompresses the firing spring 618.

To create an impaction force, the narrower tip portion 635 of the swivelrelease 633 should be placed in alignment with the central hole 625formed in the firing cylinder 622. In some embodiments, to align thenarrower tip portion 635 of the swivel release 633 with the central hole625, a user presses down on the instrument, such as on the back end 652of the handle 610. As the user presses down, the release spring 635compresses and stabilizes the swivel release 633 such that the swivelrelease 633 is aligned with the central longitudinal axis of theinstrument. Once the swivel release 633 aligns with the centrallongitudinal axis, the narrower tip portion 635 of the swivel releasewill fall into a swivel release hole 625 formed in the firing cylinder622, and will be impacted by the firing cylinder hole 625 bottoming outon the swivel release 633. The impaction force is created by thecompressed firing spring 618, and helps to drive out the graspingelement 661 through the distal end of the instrument 600. With thelocking mechanism connected to the grasping element 661, the lockingmechanism can be impacted and inserted into an anchor to thereby securethe anchor to an orthopedic device.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

What is claimed is:
 1. A method of securing an orthopedic device to bonetissue, the method comprising: positioning an anchor through an aperturein an orthopedic device, the anchor having a plurality of arms separatedby grooves, and each of the arms includes a slot formed on an innersurface of the arm; fastening the orthopedic device to bone tissue withthe anchor, locking the anchor in the orthopedic device with a lockingmechanism including a plurality of fingers corresponding to each of thearms, wherein the anchor includes one or more relief cuts disposed abovea lowermost surface of the grooves, wherein each of the slots slidablyreceives one of the plurality of fingers during downward insertion ofthe locking mechanism through the anchor causing the plurality of armsto splay outwardly to thereby secure the anchor to the orthopedicdevice, wherein each of the plurality of fingers are tapered andconfigured to engage a tapered portion of each slot, and wherein theplurality of fingers linearly and non-rotatably slide in the slot duringdownward insertion of the locking mechanism.
 2. The method of claim 1,wherein each of the slots is formed through an upper surface of itsrespective arm and extends in a direction downwardly toward a bottom ofthe anchor.
 3. The method of claim 1, wherein the grooves aresymmetrical.
 4. The method of claim 1, wherein the anchor comprises fouror more arms.
 5. The method of claim 1, wherein each of the arms aretapered.
 6. The method of claim 1, wherein the locking mechanismincludes a central circular portion.
 7. The method of claim 1, whereinthe orthopedic device is a plate member.
 8. The method of claim 1,wherein the anchor comprises a head portion, a neck portion and a shankportion with threads.
 9. The method of claim 8, wherein the neck portionincludes the one or more relief cuts.
 10. A method of securing anorthopedic device to bone tissue with an anchor positioned through anaperture in the orthopedic device, the anchor having a plurality of armsseparated by grooves, and each of the arms includes a slot formed on aninner surface of the arm, the method comprising: locking the anchor inthe orthopedic device with a locking mechanism including a plurality offingers corresponding to each of the arms, wherein the anchor includesone or more relief cuts disposed above a lowermost surface of thegrooves, wherein each of the slots slidably receives one of theplurality of fingers during downward insertion of the locking mechanismthrough the anchor causing the plurality of arms to splay outwardly tothereby secure the anchor to the orthopedic device, wherein each of theplurality of fingers are tapered and configured to engage a taperedportion of each slot, and wherein the plurality of fingers linearly andnon-rotatably slide in the slot during downward insertion of the lockingmechanism.
 11. The method of claim 10, wherein each of the slots isformed through an upper surface of its respective arm and extends in adirection downwardly toward a bottom of the anchor.
 12. The method ofclaim 10, wherein the grooves are symmetrical.
 13. The method of claim10, wherein the anchor comprises four or more arms.
 14. The method ofclaim 10, wherein each of the arms are tapered.
 15. The method of claim10, wherein the locking mechanism includes a central circular portion.16. The method of claim 10, wherein the orthopedic device is a platemember.
 17. The method of claim 10, wherein the anchor comprises a headportion, a neck portion and a shank portion with threads.
 18. The methodof claim 17, wherein the neck portion includes the one or more reliefcuts.